# -*- coding: utf-8 -*-
import numpy as np
from tools import *
from Loads import *
from ps3 import PS3

class PE3(PS3):
    elementType = "平面应变三角形单元"
    @property
    def D(self)->np.ndarray:
        """材料刚度矩阵"""
        E,nu=self.E,self.nu
        D=np.array([[1,nu/(1-nu),0],
                    [nu/(1-nu),1,0],
                    [0,0,(1-2*nu)/(2-2*nu)]])*(E*(1-nu)/(1-nu*2)*(1+nu))
        return D
